In the process of acquiring oil and/or gas from a well, it is often necessary to stimulate the flow of hydrocarbons via hydraulic fracturing. The term “fracturing” refers to the method of pumping a fluid into a well until the pressure increases to a level that is sufficient to fracture the subterranean geological formations containing the entrapped materials. This process results in cracks and breaks that disrupt the underlying layer to allow the hydrocarbon product to be carried to the wellbore at a significantly higher rate. Unless the pressure is maintained, however, the newly formed openings close. In order to open a path and maintain it, a propping agent or “proppant” is injected along with the hydraulic fluid to create the support needed to preserve the opening. As the fissure is formed, the proppants are delivered in a slurry where, upon release of the hydraulic pressure, the proppants form a pack or a prop that serves to hold open the fractures.
To accomplish the placement of the proppants inside the fracture, these particles are suspended in a fluid that is then pumped to its subterranean destination. To prevent the particles from settling, a high viscosity fluid is often required to suspend them. The viscosity of the fluid is typically managed by addition of synthetic or naturally based polymers.
Two important properties of proppants are crush strength and density. High crush strength can be desirable for use in deeper fractures where pressures are greater, e.g., greater than about 2500 psi. As the relative strength of the various materials increases, so too have the respective particle densities. Unfortunately, higher density particles are more difficult to suspend in the fluid, generally, requiring increasing the viscosity of the fracturing fluid; however, at some point, increasing the viscosity of the fluid can be detrimental to the fracking process.